1. Open the 98 and remove all the internal parts: the pins, trigger, both bolts, the valve body, etc. Until there are just the two naked receiver halves.
2. Get some steel wool or a dremel tool (make sure that if you are using a dremel that you have a wire brush insert because if you use a grinder then you can screw up your gun and the internals wont fit right) I used steel wool, takes more time but its worth it.
3. There is a black anodized coating over the inside of the two receiver halves. what you have to do is to scrap all of it off. Do not scrape any of the moving parts, or the threads!
4. After it is all gone, polish the insides of the receivers with an aluminum or chrome polish. (if you want, makes it look nice)
Pros: The anodized coating somewhat restricts the movement of the bolts. removing it makes the internals run smoother.
Cons: The anodizing helps prevent rust. if you remove it you have to clean more thoroughly and more often.